Apparatus and method for controlling transmission parameters of selected home network stations transmitting on a telephone medium

ABSTRACT

A physical layer transceiver of a home network station connected to a telephone medium has an architecture enabling adaptation of detection circuitry based on received network signals to enable reliable recovery of data signals. The physical layer transceiver includes an input amplifier that amplifies network signals according to one of 128 gain settings set by a receiver gain control signal. A signal conditioning circuit includes an envelope detector configured for outputting an envelope of the amplified received signal, and an energy detector configured for outputting an energy signal of the amplified received signals. The envelope signal and the energy signal are supplied to slicer threshold circuits, configured for outputting noise, peak, data event and energy event signals based on noise threshold, peak threshold, data transition threshold, and energy threshold signals, respectively. A digital controller controls the input amplifier gain and the threshold values, and adjusts the gain and threshold values based on the noise event signal and the peak event signal within an access ID (AID) interval. A link controller monitors the number of CRC errors in the received data packets on a per-node basis. If one transmitting station is detected as having a number of errors exceeding a first threshold, the link controller causes a reconfigure command to be output to the identified transmitting station, causing the identified transmitting station to adjust transmission parameters for improved reception reliability. The use of the reconfigure command by a receiving network node enables transmission parameters to be adjusted in selected network stations encountering severe distortion due to the topology of the home network. Alternately, the receiving network node may output an AID command packet with new power and speed settings to all transmitting network stations on the network.

FIELD OF THE INVENTION

The present invention relates to network interfacing, and moreparticularly, to methods and systems for controlling transmission ofdata between network stations connected to a telephone line.

DESCRIPTION OF THE RELATED ART

Local area networks use a network cable or other media to link stationson the network. Each local area network architecture uses a media accesscontrol (MAC) enabling network interface cards at each station to shareaccess to the media.

Conventional local area network architectures use media accesscontrollers operating according to half-duplex or full duplex Ethernet(ANSI/IEEE standard 802.3) protocol using a prescribed network medium,such as 10 BASE-T. Newer operating systems require that a networkstation to be able to detect the presence of the network. In an Ethernet10 BASE-T environment, the network is detected by the transmission of alink pulse by the physical layer (PHY) transceiver. The periodic linkpulse on the 10 BASE-T media is detected by a PHY receiver, whichdetermines the presence of another network station transmitting on thenetwork medium based on detection of the periodic link pulses. Hence, aPHY transceiver at Station A is able to detect the presence of StationB, without the transmission or reception of data packets, by thereception of link pulses on the 10 BASE-T medium from the PHYtransmitter at Station B.

Efforts are underway to develop an architecture that enables computersto be linked together using conventional twisted pair telephone linesinstead of established local area network media such as 10 BASE-T. Suchan arrangement, referred to herein as a home network environment,provides the advantage that existing telephone wiring in a home may beused to implement a home network environment. However, telephone linesare inherently noisy due to spurious noise caused by electrical devicesin the home, for example dimmer switches, transformers of homeappliances, etc. In addition, the twisted pair telephone lines sufferfrom turn-on transients due to on-hook and off-hook and noise pulsesfrom the standard POTS telephones, and electrical systems such asheating and air conditioning systems, etc.

An additional problem in telephone wiring networks is that the signalcondition (i.e., shape) of a transmitted waveform depends largely on thewiring topology. Numerous branch connections in the twisted pairtelephone line medium, as well as the different associated lengths ofthe branch connections, may cause multiple signal reflections on atransmitted network signal. Telephone wiring topology may cause thenetwork signal from one network station to have a peak-to-peak voltageon the order of 10 to 20 millivolts, whereas network signals fromanother network station may have a value on the order of one to twovolts. Hence, the amplitude and shape of a received pulse may be sodistorted that recovery of a transmit clock or transmit data from thereceived pulse becomes substantially difficult.

SUMMARY OF THE INVENTION

There is a need for a network station having a physical layertransceiver capable of reliably recovering data from a received networksignal on a telephone line medium.

There is also a need for a network station, receiving network signalsfrom different network nodes on a telephone line medium, to minimizeloss of data due to distortion caused by telephone wiring topology on aper-node basis.

There is also need for an arrangement for a network station receivingnetwork signals from network nodes on a telephone line medium toovercome distortion effects caused by the telephone line medium byselectively adjusting transmitter performance on a node-specific basis.

These and other needs are attained by the present invention, where anetwork station receiving data packets from different network stationson a telephone line medium selectively outputs a configuration packethaving a prescribed destination address, based on detected errors in thereceived data packets, that causes a selected network stationscorresponding to the destination address to adjust transmissionparameters for improved reception reliability.

According to one aspect of the present invention, a network stationconfigured for sending and receiving network signals between othernetwork stations on a telephone line medium includes a media accesstransceiver configured for receiving first data packets from thetelephone line medium and transmitting second data packets onto thetelephone line medium at a selected output gain and transmission speed,and is also configured for detecting a presence of an error in the firstdata packets. The network station also includes a link controllerconfigured for causing the media access transceiver to output onto thetelephone line medium a configuration data packet, having a selecteddestination address corresponding to a selected one of the other networkstations, based on the detected errors in the first data packets fromthe selected one network station reaching a first prescribed threshold.The configuration data packet causes the selected one network station toadjust at least one transmission parameter for reduction of the errorsin received data packets. The detection of errors in data packets fromthe selected one network station enables the link controller to monitorthe relative performance of different transmitting network stations todetermine which network station have a relatively high error rate due todistortion effects caused by the telephone line medium. Hence, the linkcontroller can output a configuration data packet to a selected networkstation, enabling the selected network station to individuallyreconfigure its corresponding transmission parameters to overcomedistortion effects caused by telephone wiring topology. Hence, areceiving network station can control transmission parameters ofselected stations encountering severe distortion relative to othernetwork nodes on the telephone line medium.

Another aspect of the present invention provides a method in a networkstation of controlling transmission of data packets by other networkstations via telephone line medium. The method includes receiving thedata packets from the other network stations via the telephone linemedium, determining a number of errors in data packets from one of theother network stations exceeding a first prescribed threshold, andoutputting onto the telephone line medium a configuration packet to theone network station based on the corresponding number of errorsexceeding the first prescribed threshold.

Still another aspect of the present invention provides a method oftransmitting data between a plurality of network stations connected to atelephone line medium. The method includes transmitting data packetsfrom transmitting network stations onto the telephone line medium inaccordance with respective transmission parameters. The transmitted datapackets are received in the second network station from the telephoneline medium and a number of errors are identified in the transmitteddata packets from at least one of the transmitting network stations. Themethod also includes transmitting a configuration data packet from thesecond network station to the one transmitting network station via thetelephone line medium in response to the number of errors correspondingto the one transmitting network station exceeding a first prescribedthreshold, and changing at least one of the corresponding transmissionparameters by the one transmitting network station in response toreception of the configuration data packet.

Additional advantages and novel features of the invention will be setforth in part in the description which follows, and in part will becomeapparent to those skilled in the art upon examination of the followingor may be learned by practice of the invention. The advantages of theinvention may be realized and attained by means of the instrumentalitiesand combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the attached drawings, wherein elements having thesame reference numeral designations represent like elements throughoutand wherein:

FIG. 1 is a block diagram illustrating a local area network deployedover residential twisted pair wiring.

FIGS. 2A, 2B, 2C and 2D are diagrams illustrating processing of receivedwaveforms by the physical layer transceiver of FIG. 1 according to anembodiment of the present invention.

FIG. 3 is a block diagram illustrating the architecture of the physicallayer transceiver of FIG. 1 according an embodiment of the presentinvention.

FIG. 4 is a flow diagram illustrating the method of requestingcontrolling transmission parameters according to an embodiment of thepresent invention.

FIG. 5 is a diagram of a link controller within the network station forcontrolling transmission parameters according to an embodiment of thepresent invention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a diagram of an Ethernet (IEEE 802.3) local area network 10implemented in a home environment using twisted pair network mediaaccording to an embodiment of the invention. As shown in FIG. 1, thenetwork 10 includes network stations 12a and 12b that are connected to atelephone line (twisted pair) wiring 14, via RJ-11 phone jacks 16a and16b respectively. A telephone 18 connected to the RJ-11 phone jack 16cmay continue to make phone calls while stations 12a and 12b arecommunicating.

As shown in FIG. 1, each network station 12, for example a personalcomputer, printer, or intelligent consumer electronics device, includesa physical layer (PHY) transceiver 20, a media access (MAC) layer 22,and an operating system (OS) layer that performs higher layer functionaccording to the OSI reference model.

The stations 12a and 12b communicate by transmitting band limited pulsesthat carry network data modulated in the analog network signals. Inparticular, the physical layer transmitter transmits a band limitedpulse 5, illustrated in FIG. 2A. The arrival position of a receivedpulse is detected using a waveform envelope 8 representing the absolutevalue 6 of the received signal, shown in FIG. 2B. The envelope 8 issupplied to a slicing circuit described below, having a threshold level9 selected to identify the arrival position 11 of the received pulse.When the envelope 8 crosses the threshold level 9, the slicing circuitdetects the arrival position 11 of the pulse as an event representing adata pattern. This event can be used to recover a transmit clock andtransmit data from the received signal.

However, in telephone wire networks, the received envelope waveformdepends largely on the wiring topology. As the wiring topology may causemultiple signal reflections, the shape of a received pulse may be sodistorted that the envelope may have multiple localized maximum points.In addition, the wiring topology in the home network is variable. Hencethe distortion of the received pulse is unpredictable, resulting in awaveform 26 as shown in FIG. 2C. As shown in FIG. 2C, the distortedwaveform 26 of a received pulse signal has multiple localized maximumand minimum points 26a and 26b due to wiring topology. FIG. 2Dillustrates the envelope waveform 28 of the distorted waveform 26.Hence, if a threshold value is not properly set for detection of a datapulse, a slicing circuit may identify multiple pulse positions at whichcrosses a threshold level. As a result, a unique time value for theposition of a received pulse may not be detected resulting in datarecover errors.

According to the disclosed embodiment, an adaptive physical layertransceiver architecture adaptively adjusts the signal processingcircuitry on both the receive side and transmit side to optimizeaccurate recovery data from the transmitted network signals, andoptimize transmitter performance to overcome adverse conditions due tohome telephone wiring topology. In particular, the disclosed embodimentincludes a link controller within the network station 12, for examplecontrol routines within the OS layer 24 executable by the hostmicroprocessor or logic circuitry implemented in the OS layer 24 or theMAC 22. The link controller monitors the number of errors in receiveddata packets and selectively controls the output of command packets ontothe network 10, causing other network stations receiving the commandpackets to improve their respective transmission characteristics. Theimprovement of transmission characteristics, for example increasing anoutput amplifier gain or reducing a data transmission rate, enables thetransmitted data packet to be more reliably received by a receivingnetwork station, reducing the bit error rate of received data packets.An overview of the physical layer transceiver architecture will first beprovided, followed by a description of the arrangement for controllingtransmission levels in transmitting network stations.

Physical Layer Architecture

FIG. 3 is a block diagram of the physical layer transceiver 20 accordingto an embodiment of the present invention. As shown in FIG. 3, thephysical layer transceiver 20 includes an input amplifier 30 foramplifying analog network received from the telephone medium, such asthe network signals shown in FIG. 2C. As described below, the inputamplifier 30 has a variable gain controlled by a 7-bit gain signal(R×Gain) for amplifying received network signals. The physical layertransceiver 20 also includes a signal conditioning circuit 32 thatincludes an envelope detection circuit 34 and an energy detectioncircuit 36. The envelope detection circuit 34 generates the envelopesignal 28 in response to the amplified received signal 26. For example,the envelope detector 34 includes an absolute value circuit (e.g., arectifier circuit) that generates an absolute value signal 39 of theamplified received signal 26, and a low pass filter coupled to therectifier circuit for filtering out high-frequency components therectified signal, resulting in the envelope signal 28. The envelopesignal 28 is output from the envelope detector 34 and supplied to theenergy detector 36. The energy detector 36 includes an integrator whichperforms the mathematical process of integration over time to produce asignal proportional to energy of the received pulse signal.

As shown in FIG. 3, physical layer transceiver 20 also includes aplurality of slicer circuits 38, and a digital to analog converter 40for supplying analog threshold signals to the slicer circuits 38. Thephysical layer transceiver also includes a digital controller 41configured for controlling the digital analog converter 40 foroutputting the threshold signal E, N, D, P, described below.

In particular, the digital controller 41 is configured for controllingthe threshold values applied to the slicers 38a, 38b, and 38d based onthe signals supplied by the slicers 38 to the digital controller 41. Inparticular, slicer circuit 38a outputs a peak event signal indicatingwith respect to time whether the envelope signal 28 exceeds a peakthreshold (P) supplied by the digital to analog converter 40 under thecontrol of the digital controller 41. Slicer circuits 38b and 38c outputdata event signals and noise event signals indicating with respect totime whether the envelope signal 28 exceeds a data transition threshold(D) and a noise threshold (N) respectively. The slicer circuit 38doutputs an energy event signal indicating with respect to time whetherthe energy signal output by energy detector 36 exceeds an energythreshold (E) supplied by the D/A converter 40.

Hence, the slicer circuits 38a, 38b, and 38c output peak, datatransition, and noise event signals indicating with respect to timewhether the envelope signal 28 exceeds a peak threshold (P), a datatransition threshold (D), and a noise threshold (N), respectively.Slicer 38d, however, outputs an energy event signal indicating withrespect to time whether the energy signal from the energy detector 36exceeds an energy threshold (E).

The digital controller 41 controls the noise, peak and data transitionthresholds based on the noise event signals and the peak signals outputby the slicers 38c and 38a, respectively, and outputs digital datasignals to the media access controller 22 via a media independentinterface (MII) 50 based on either the energy event signals or the dataevent signals.

In particular, the digital controller 41 adjusts the gain of theamplifier 30, and the threshold values P, D, N, and E generated by the Dto A converter 40 during an access ID (AID) interval. AID is a specificidentifier which is unique for each network station 12. AID is a seriesof 8 pulses output from the PHY transceiver 20 of the transmittingstation onto the telephone medium 14, where the time intervals betweenthe first pulse and the successive 7 pulses define respective values.For example, assume a second pulse is output by the PHY transceiver 20following a first pulse at time T1. If T1 equals 66 clock cycles(assuming a 116 nanosecond clock), the corresponding value is 00; if T1equals 86, 106, or 126 clock cycles, the values are 01, 10, or 11,respectively, where the maximum interval between pulses is 128 clockcycles. The same arrangement is used to detect the values used in timeintervals T2, T3, T4, T5, and T7. Hence, the presence of the valid AIDcan be determined by detecting a first pulse, and detecting a presenceof 7 successive pulses using detection windows each having a duration of128 clock cycles.

According to the disclosed embodiment, AID replaces the preambleconventionally used in 10 Base-T Ethernet (IEEE 802.3) systems. Hence,the digital controller 41 of the present invention uses the AID intervalto selectively tune the input amplifier 30 to one of 128 different gainsettings selected by the R×Gain signal, and set the threshold valuesused by the slicer circuits 38 by supplying digital threshold values tothe D/A converter 40. Once the digital controller 41 has tuned the inputamplifier 30 and the threshold values of the slicer circuits 38, thedigital controller 41 uses either the data transition event signals fromthe slicer circuit 38b or the energy event signal from the slicercircuit 38d for recovering the data signals, described below.

The physical layer transceiver also includes a transmitter portion 52(e.g., an output current amplifier), that converts transmit data (T×D)to an analog network signal. The analog network signal is output at aselected one of 128 output gain values based on the 7-bit transmit gain(T×Gain) signal output by the digital controller 41.

As shown in FIG. 3, the physical layer transceiver 20 also includes anoutput interface 42 including an MII to general purpose serial interface(GPSI) converter 44, management interface logic 46, and buses 48a and48b. The bus 48a transfers transmit and receive data between the MAC 22and the digital controller 41 in GPSI format. The converter 44 convertsthe GPSI format data to nibble-wide data for transfer to the MAC 22 viathe MII 50. Similarly, transmit data from the MAC 22 supplied via theMII 50 is converted from nibble-wide data to GPSI format, and suppliedto the digital controller 41 via the GPSI data bus 48a.

The output interface 42 also includes a control data bus 48b fortransferring configuration data and status information between thedigital converter 41 and the management interface logic 46. Inparticular, the management interface logic 46 is configured for storingconfiguration data, received from the MAC 22 via the MII 50, into thedigital controller 41 at selected control registers 60. Note that thethreshold value E for the energy detector slicer circuit 38d may besupplied by the management agent via the MII 50 and set in theconfiguration registers 60. The digital controller 41 also includesstatus registers 62 that include, for example, the threshold values forthe threshold signals P, D, and E, and the 7-bit input and outputamplifier gain control signals (R×Gain, T×Gain). Hence, a managementagent (e.g., a link controller, described below) can access registers 60and 62 for reading and writing of control information, and readingstatus information from the status registers 62. The interface 42 alsoincludes link detection logic 47 for determining whether a valid link isdetected on the network medium 14. If no valid AID is detected withinthree successive detection intervals, each having a preferred durationof about 800 milliseconds, the link status is sent to an invalid state.A valid AID may be either a link packet or a preamble for a data packet.

Controlling Transmission Parameters of Selected Stations

FIG. 5 is a diagram of a link controller within the network station forcontrolling transmission parameters according to an embodiment of thepresent invention. As shown in FIG. 5, the link controller 80 is part ofthe operating system 24, which may be implemented as a driver softwareexecutable by a host microprocessor, or as a state machine implementedin silicon. The link controller system includes the link controller 80having an internal timer 82. The system also includes a plurality ofmemories 84, an error counter 86, and a table 88 configured for storingmedia access control source addresses (MAC SA) for different networkstation 12 having transmitted data packet to the receiving networkstation within a prescribed detection interval counted by the timer 82(e.g., 1 second). In particular, the table 88 stores the source addressof each received data packet having a detected CRC error. For example,the link controller 80 stores in table 88 a source address of a firstnetwork station (SA 1) having transmitted a data packet that had adetected CRC error. Similarly, the entries SA 2 and SA 3 represent MACaddresses of other network stations having transmitted data packets withdetected CRC errors. As shown in FIG. 5, the table 88 tracks the MACaddresses for each of the network stations having transmitted datapackets with errors, plus the number of CRC errors detected from thecorresponding transmitting stations in the column entitled "MAC SAErrors". Hence, the sum of the errors in the table 88 equal the errorcount in the CRC error counter 86 during the detection interval countedby the timer 82. As described below, the error count in the counter 86and the table 88 are cleared at the end of each 1 second detectioninterval.

FIG. 4 is a diagram illustrating the method by the link controller 80 ofcontrolling the transmission parameters of selected network stationsaccording the an embodiment of the present invention. The linkcontroller 80 first fetches the transmit power level (T×Gain) and thetransmit data rate from the memories 60 and 62 in the PHY 20, and storesthe transmit power level and transmit data rate in memories 84a and 84b,respectively (step 90). The link controller 80 then sets the total CRCthreshold (CRCperSec) and the CRC station threshold (CRCperStation) inmemories 84c and 84d, respectively (step 92). The CRC per secondthreshold had a default value of 10, and represents the thresholdcausing the link controller 80 to output an AID command packet to allnetwork stations if the CRC counter 86 exceeds this threshold. The CRCper station threshold, having default value of 5, represents thethreshold value at which the link controller 80 outputs a reconfigurecommand packet to a specific station if the number of CRC errorsgenerated by the specific station exceeds the threshold value.

Following step 92, the link controller 80 enters a run time state, wherethe media access transceiver 23 (composed of the PHY 20 and the MAC 22)receives data packets from transmitting network stations. In particular,the PHY 20 recovers the data stream, and the MAC 22 detects whetherthere is a CRC error present in any of the received data packets.

The link controller 80 determines whether there are any CRC errors in areceived packet in step 94 during transfer of the received data packetfrom the MAC 22 to the system memory by the OS 24. If the linkcontroller 80 detects a CRC error, the link controller 80 increments theerror counter 86, saves the source address of the received packet in thetable 88, (e.g., SA 1), and increments the MAC SA Errors column of table88 in step 96. Hence, the link controller 80 uses table 88 to keep trackof the CRC errors on a per-node basis. The link controller 80 keepstrack of the error detection interval (EDI) using timer 82, and checksin step 98 if the error detection interval has expired. If the errordetection interval has not expired, the link controller 80 continues tomonitor for detected errors for the corresponding transmitting networknodes.

If in step 98 the error detection interval has expired, the linkcontroller 80 checks in step 100 whether the error counter 86 exceedsthe overall CRC per second threshold stored in memory 94c. If the CRCerror counter value 86 exceeds the threshold value stored in memory 84c,the link controller 80 checks in step 102 if all the CRC errors arecaused by the same source address. If all CRC errors are caused by thesame source address (i.e., the same transmitting network station), thelink controller 80 causes the MAC 22 to output a reconfigure command tothe network station having the identified source address in step 104. Inparticular, the link controller forwards the identified source address(MAC SA) to the MAC 22, which generates the reconfigure command byplacing the supplied source address (e.g., SA 1) as the destinationaddress for the reconfigure command packet. The destination networknode, upon receiving the reconfigure command data packet, recognizesitself as the destination for the reconfigure command packet bycorrelating the destination address, and reconfigures the transmissionparameters by increasing the output power and/or reducing the outputdata rate to 700 kb/s. After reconfiguring itself, the destination nodeignores any subsequent reconfiguration command packet for an arbitrarytime period (e.g., 10 seconds).

Assuming in step 102 that all the errors counted by counter 86 were notfrom the same source address, the link controller 80 checks in step 106to determine which MAC source address had the highest number of CRCerrors. The link controller 80 then checks in step 108 whether theidentified MAC source address having the greatest number of errorsexceeds the CRC per station threshold stored in memory 84d. If theidentified network station exceeds the CRC per station threshold, thelink controller 80 causes the MAC 22 to output the reconfigure commandpacket the identified MAC address in step 104. However, if in step 108the MAC address having the highest number of CRC errors does not exceedthe CRC per station threshold, the link controller 80 causes the MAC 22to output an AID command packet that specifies new output power and newtransmit speed settings for all the network stations in step 110. Hence,the AID command is used in step 110 to improve transmission performancefor all network stations generally, whereas the link controller 80 usesstep 104 to improve the transmission performance of a selected networkstation.

Following the output of the reconfigure command in step 104 or the AIDcommand in step 110, the link controller 80 resets the error counter 86and clears the table 88 in step 112 to begin monitoring for a new errordetection interval.

Assuming in step 100 that the CRC error counter 86 does not exceed theCRC per second threshold stored in memory 84c, the link controller 80then checks in step 116 if the error counter 86 exceeds the CRC perstation threshold stored in memory 84d. If the error counter 86 does notequal or exceed the minimum threshold CRC per station stored in memory84d, then performance by the transmitting stations is deemed acceptable,the counter 86 and table 88 are cleared in step 112, and monitoringresumes in step 94. However, if in step 116 the error counter 86 exceedsthe minimum threshold of the CRC per station, the link controller 86checks in step 118 if all the errors are caused by the same MAC sourceaddress. If all the errors are from the same MAC source address in step118, the link controller 80 causes the reconfigure command to be outputto the identified transmitting network station in step 104. However, ifall the errors were not caused by the same MAC source address in step118, the link controller 80 identifies the MAC source address having themost CRC errors in step 120. If the identified MAC address has acorresponding number of errors greater than the lower threshold of theCRC per station in step 122, the link controller 80 causes thereconfigure command to be output to the identified MAC source address instep 104. Otherwise, the error counter 86 and the table 88 are clearedin step 112, and monitoring continues.

According to the disclosed embodiment, CRC errors from received datapackets are monitoring on a per station basis. Hence, a receivingnetwork station can identify those network stations encountering severedistortion caused by telephone wiring topology relative to other networkstations, and send a data packet to the identified network station toimprove transmission parameters. Hence, transmitting stationsencountering severe degradation can improve their transmissionperformance, without causing other transmitting stations encounteringminimal distortion to unnecessarily increase the output power. Moreover,the disclosed arrangement can be used to enable each of the transmittingnetwork stations to intelligently track which station require extratransmission performance due to telephone networking topology. Forexample, a transmitting network station may track a number ofreconfiguration packets received from different network stations, andselectively change its transmission performance depending on thedestination of a transmitted packet.

While this invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not limited to thedisclosed embodiments, but, on the contrary, is intended to covervarious modifications and equivalent arrangements included within thespirit and scope of the appended claims.

What is claimed is:
 1. A network station configured for sending andreceiving network signals between other network stations on a telephoneline medium, the network station including a media access transceivercomprising:a physical layer transceiver configured for receiving firstdata packets from the telephone line medium and transmitting second datapackets onto the telephone line medium at a selected output gain andtransmission speed; a media access controller layer; and an operatingsystem layer connected according to Open Systems Interconnection (OSI),the media access controller configured for receiving digital signalstransferred from the physical layer transceiver and for detecting apresence of an error in the first data packets, and the operating systemlayer including a link controller configured for causing the physicallayer transceiver to output onto the telephone line medium aconfiguration data packet, having a selected destination addresscorresponding to a selected one of the other network stations, based onthe detected errors in the first data packets from the selected onenetwork station reaching a first prescribed threshold, the configurationdata packet causing the selected one network station to adjust at leastone transmission parameter for reduction of the errors in received datapackets.
 2. The network station of claim 1, wherein the link controllercomprises an error counter for counting a total number of the detectederrors for the other network stations within a prescribed time interval,the link controller causing the physical layer transceiver to output acontrol data packet to the other network stations in response to theerror counter reaching a second prescribed threshold greater than thefirst prescribed threshold.
 3. The network station of claim 2, whereinthe link controller further comprises a table for storing sourceaddresses of the first data packets having the detected errors and acount of the detected errors from the corresponding network station, thelink controller configured for outputting the configuration data packetto the selected one network station in response to the correspondingcount reaching the first prescribed threshold.
 4. The network station ofclaim 1, whereinthe physical layer transceiver has first and secondregisters for storing a link speed and the selected output gain used fortransmission of the second data packets, respectively, and the mediaaccess controller layer hs an error detection circuit configured fordetecting said error in the first data packets.
 5. The network stationof claim 1, wherein the link controller includes a table for storingsource addresses of the first data packets having the detected errorsand a count of the detected errors from the corresponding networkstation, the link controller configured for outputting the configurationdata packet to the selected one network station in response to thecorresponding count reaching the first prescribed threshold.
 6. Thenetwork station of claim 5, wherein the physical layer transceiveroutputs a control data packet as an access identifier (AID) controlpacket to the other network stations in response to a total number ofthe detected errors for the other network stations reaching a secondprescribed threshold greater than the first prescribed threshold.